Switch to ttyS0 as console device

JOURNAL.md

@@ -4297,3 +4297,17 @@ least).
 
 Disabling udev by just setting `services.udev.enable = false` doesn't work. It
 still gets activated by the kernel socket.
+
+## 2024-09-30
+
+Managed to launch an interactive shell from stage2, before we run systemd. It
+boots in less than 5 minutes.
+
+Now I can run some benchmarks there.
+
+Let's see if I can enable flow control on the serial console. That would be
+helpful.
+
+For that I need to first switch to the 8250/16550 driver. Let's try switch to
+the ttyS0 without enabling flow control yet. We probably need to change the
+stage1 and stage2 scripts to follow the proper console device.

lagarto-ox.nix

@@ -511,7 +511,7 @@
     in prev.runCommand "uboot.txt" {} ''
       cat > $out <<EOF
       xtrace=yes
-      bootargs=root=/dev/ram0 loglevel=7 rw earlycon=sbi console=hvc0 debug2 init=${init}
+      bootargs=root=/dev/ram0 loglevel=7 rw earlycon=sbi console=ttyS0,115200n8 debug2 init=${init}
       ramdisk_size=$(stat --format %s $(readlink -f ${initrd}))
       bootcmd=fdt print; booti \''${kernel_addr_r} \''${ramdisk_addr_r}:\''${ramdisk_size} \''${fdtcontroladdr}
       EOF